An Espressif ESP32 microcontroller forms the core of this DIY metal detector project
Paired with the usual support circuitry, the ESP32 generates the required pulses and senses the resulting field from a search coil
The smartphone communicates with the ESP32 via Bluetooth, providing an interface to display detection data and alerts, for example, when a target metal object is found.
While the Arduino sketch running on the ESP32 is fairly straightforward, the smartphone app carries out any necessary Fourier transforms to analyse the detected signals and alert the user to target objects.
— A previous version of this story incorrectly stated the ESP32 performed these transforms.
